From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0801FC433F5 for ; Sun, 17 Apr 2022 16:30:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234392AbiDQQdQ (ORCPT ); Sun, 17 Apr 2022 12:33:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35888 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234358AbiDQQdL (ORCPT ); Sun, 17 Apr 2022 12:33:11 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 627CEA199 for ; Sun, 17 Apr 2022 09:30:35 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 0EF8DB80CBF for ; Sun, 17 Apr 2022 16:30:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B171CC385A4; Sun, 17 Apr 2022 16:30:30 +0000 (UTC) Date: Sun, 17 Apr 2022 17:30:27 +0100 From: Catalin Marinas To: Herbert Xu Cc: Ard Biesheuvel , Will Deacon , Marc Zyngier , Arnd Bergmann , Greg Kroah-Hartman , Andrew Morton , Linus Torvalds , Linux Memory Management List , Linux ARM , Linux Kernel Mailing List , "David S. Miller" Subject: Re: [PATCH 07/10] crypto: Use ARCH_DMA_MINALIGN instead of ARCH_KMALLOC_MINALIGN Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Apr 17, 2022 at 04:58:29PM +0800, Herbert Xu wrote: > On Sun, Apr 17, 2022 at 09:50:50AM +0100, Catalin Marinas wrote: > > > > Right, if that's what you prefer. Something like: > > > > diff --git a/include/linux/crypto.h b/include/linux/crypto.h > > index 2324ab6f1846..bb645b2f2718 100644 > > --- a/include/linux/crypto.h > > +++ b/include/linux/crypto.h > > @@ -645,7 +645,7 @@ struct crypto_tfm { > > > > struct crypto_alg *__crt_alg; > > > > - void *__crt_ctx[] CRYPTO_MINALIGN_ATTR; > > + void *__crt_ctx[] __aligned(ARCH_DMA_MINALIGN); > > }; > > > > But once we do that, are there any other CRYPTO_MINALIGN left around? > > This is still implying the whole structure is aligned to the given > value, which it is not. > > Please just add the padding as needed. Do you mean as per Ard's proposal here: https://lore.kernel.org/r/CAMj1kXH0x5Va7Wgs+mU1ONDwwsazOBuN4z4ihVzO2uG-n41Kbg@mail.gmail.com struct crypto_request { union { struct { ... fields ... }; u8 __padding[ARCH_DMA_MINALIGN]; }; void __ctx[] __aligned(CRYPTO_MINALIGN); }; If CRYPTO_MINALIGN is lowered to, say, 8 (to be the same as lowest ARCH_KMALLOC_MINALIGN), the __alignof__(req->__ctx) would be 8. Functions like crypto_tfm_ctx_alignment() will return 8 when what you need is 128. We can change those functions to return ARCH_DMA_MINALIGN instead or always bump cra_alignmask to ARCH_DMA_MINALIGN-1. -- Catalin